how to fix P0420 code on my Genesis G70 IG (2017-2023)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface, and use wheel chocks for safety.
• Disconnect the battery to prevent electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (Bank 1) using the O2 sensor socket.
• Inspect the sensor for damage; if necessary, replace it with a new sensor.
• Install the new sensor and torque to manufacturer specifications (usually around 30 ft-lbs).
• Repeat the process for the downstream oxygen sensor if needed.

3. Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, gasket scraper, exhaust sealant.
• If the catalytic converter is confirmed faulty, lift the vehicle safely using jack stands.
• Remove the exhaust pipes connected to the catalytic converter using a socket set.
• Use a gasket scraper to clean the mating surfaces on the exhaust system.
• Install the new catalytic converter with new gaskets and torque bolts to specifications (usually around 25 ft-lbs).
• Reconnect the exhaust system and ensure all clamps and seals are tight.

4. Reset the Engine Control Module (ECM)

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECM.
• Start the engine and allow it to run for a few minutes.